Design and characterization of MEMS based micrograsping system

This paper aims to present design and characterization of a micrograsping system which is capable of safely grasping micro‐objects.

The proposed micrograsping system consists of novel MEMS based microgripper integrated with capacitive contact sensor (fabricated in standard micromachining process SOI‐MUMPs), sense electronics, a controller, high voltage actuation circuit and graphical user interface.

Due to the improvement in the lateral comb‐drive design, the actuator requires low actuation voltages in the range of 0‐45 V. This requires a simple and low power actuation circuitry. Capacitive feedback control mechanism is used in the sensor to detect the contact between the jaws and micro‐object while providing high values of the capacitance.

The designed sense electronics can sense the capacitance ranging from 0‐330 fF. Due to the availability of integrated contact sensor, objects ranging from 54 μm to 70 μm can be gripped safely with the applied maximum force of 220 μN at the tip of the gripper.

The performance of the microgripper, controller algorithm and associated electronics were experimentally quantified through the gripping of 65 μm sized human hair.